Chad Perrin: SOB

15 November 2008

First AL Whitepaper — Deadline Math

Filed under: Geek,Profession — apotheon @ 04:07

I’ve published my first Apotheonic Labs Whitepaper. I’m considering renaming them Blackpapers, or Bluepapers, or maybe BlackAndBluePapers. I’m not sure how well BABPapers would play in Peoria.

(The remainder of this SOB entry is heavily edited to reflect information that was not on my mind when I first wrote it.)

On roughly the same subject as the first Apotheonic Labs Whitepaper is a recent article by Sterling Camden at Tech Republic’s IT Consulting Weblog, titled Giving IT consulting clients realistic estimations. In it, he explains his simplified formula for estimating the time (and money, since that’s based on time) you need as a consultant to complete a project:

T = (G * U) / R

It’s a good article, and it’s recommended reading for anyone that has to provide project completion time estimates.

The first AL Whitepaper is an explanation of the mathematical realities of deadline specifications for consulting projects. These are the Laws of Nature as they apply to calculating the actual date of a deadline, once you’re done coming up with the estimate itself.

Yes, that’s right — you still need to be able to calculate time to completion after you produce an estimate. The estimate is not simply an answer to the question. It’s just the basis for determining the actual answer. The whitepaper is called:

Deadline Math

The introduction goes something like this:

Project completion date estimation is something of a dark art. It is less science than mysticism and intuition. Some of us are quite good at it, and some not so much. One of the problems people often encounter with accurate project completion is specification creep. There is a simple answer to this problem, however: Deadline Math.

Deadline Math is not quite the same beast as normal mathematics because it makes use of some underlying assumptions that most people never notice. Once they are brought to one’s attention, however, they may look like common sense. In the interests of making my life easier — by helping my clients understand one of the most important factors in accurate project completion estimation — as well as the interests of helping my fellow developers better practice the art of project completion estimation, I’ll explain Deadline Math in brief, by way of an explanation of how I use it.

If that doesn’t pique your interest, I’m not sure what will.

sshd_config: GatewayPorts for error-free proxy

Filed under: Geek,Security — apotheon @ 01:27

Note to self:

When using SSH as a secure proxy for Web browsing and IMs, to protect myself from eavesdroppers on public wireless networks, make sure you have the following two options set in the sshd_config file on the system you’re using as the remote proxy:

AllowTcpForwarding yes
GatewayPorts       yes

The AllowTcpForwarding option should be “yes” by default (as is the case with FreeBSD), anyway. GatewayPorts, on the other hand, is “no” by default. When GatewayPorts is set to “no”, you’ll probably be able to do (almost?) all your Web browsing and IMing through the proxy, but you’ll get error messages in the terminal emulator window you’re using for the SSH connection that look something like this:

channel 6: open failed: administratively prohibited: open failed
channel 8: open failed: administratively prohibited: open failed
channel 14: open failed: administratively prohibited: open failed
channel 15: open failed: administratively prohibited: open failed
channel 21: open failed: administratively prohibited: open failed
channel 21: open failed: administratively prohibited: open failed
channel 12: open failed: administratively prohibited: open failed
channel 31: open failed: administratively prohibited: open failed
channel 8: open failed: administratively prohibited: open failed
channel 26: open failed: administratively prohibited: open failed
channel 16: open failed: administratively prohibited: open failed
channel 16: open failed: administratively prohibited: open failed
channel 10: open failed: administratively prohibited: open failed
channel 11: open failed: administratively prohibited: open failed
channel 10: open failed: administratively prohibited: open failed

In other news — if anyone knows why I can’t get freebsd.org to load when I’m using an SSH SOCKS proxy, please tell me. I haven’t figured that one out yet. I know changing the UseDNS option’s setting on the server doesn’t fix the problem, even though that seems like the obvious answer.

EDIT:

Actually, you might still get those administratively prohibited errors even with the GatewayPorts options set. C’est la vie.

All original content Copyright Chad Perrin: Distributed under the terms of the Open Works License